1. Field of the Invention
The present invention relates to color processing for converting image data of an input device into that for an output device, and installation, uninstallation, and creation of conversion characteristic data for the color processing.
2. Description of the Related Art
Japanese Patent Application Laid-Open No. 2000-50086 describes a method of implementing high-precision color matching between an input image and output image independently of the viewing conditions on the input side and output side. This technique initially converts input data which depends on the color space of an input device into data of a color space that does not depend on any devices based on the viewing conditions on the input side via a conversion table, conversion matrix, or conversion function (to be collectively referred to as a “conversion function” hereinafter). Note that the color space of the input device will be referred to as an “input color space,” the color space that does not depend on any devices will be referred to as a “device-independent color space (DIC),” and the color space of an output device will be referred to as an “output color space” hereinafter. Next, a forward converter converts the data of the DIC into data of a human color appearance space. Then, on the color appearance space, gamut mapping is executed to absorb differences between a gamut of the input device and a gamut of the output device. An inverse converter then converts the data of the color appearance into data of a DIC based on the viewing conditions on the output side. Finally, the data of the DIC is converted into output data of the output color space by the conversion function.
Creation of the conversion function requires complicated arithmetic processing and much time. Therefore, when the conversion function is created according to the viewing conditions for every color matching, high-speed color matching processing cannot be attained.
Hence, the technique of Japanese Patent Application Laid-Open No. 2000-50086 caches the created conversion function, and executes actual color matching processing using the cache data, thus speeding up the color matching processing.
FIG. 1 is a block diagram showing the practical arrangement of a color matching system.
A source device color converter 101 converts data of the color space of a source device into data of a DIC. A gamut mapping unit 102 maps the gamut of the data input from the source device color converter 101 onto that of a destination device. A destination device color converter 103 converts the data input from the gamut mapping unit 102 into data of the color space of the destination device.
In such color matching system, if respective color conversions are applied to input color data by calculations, enormous amounts of time are required. Hence, a technique that creates a lookup table (LUT) by integrating a plurality of color conversions, and applies color matching to input color data using the created lookup table has been proposed. However, when the plurality of color conversions are integrated every time color matching is applied to the input color data, integration of the color conversions requires much time, and may cause a throughput drop of the color matching processing. In order to suppress the throughput drop, data of the integrated color conversion (to be referred to as “integrated color conversion data” hereinafter) may be cached. However, the integrated color conversion data must be created at least once per color matching, and the throughput drops at that time.